Facsimile transmission and reception has become a common means for communicating images over the Public Switched Telephone Networks (PSTN). Conventional facsimile machines use the PSTN to send copies of images to specified recipients anywhere in the world. Generally, a single facsimile machine is used to service several potential recipients. It is therefore a problem to assure that the transmitted document reaches its intended recipient. In conventional facsimile, cover sheets are normally used for the conveyance of addressing and routing information. However, these cover sheets comprise an additional image which is sent prior to the intended images, and use a relatively large amount of resource, PSTN time, facsimile-machine time, paper, etc., for relatively little information. Further, such cover sheets are only human interpretable.
In recent years, the facsimile arts have further advanced with the development of adapter cards and programming, which permit small computers to scan in images, or convert text and graphic data to images which can be transmitted via the PSTN sent by a facsimile modem on the adapter card. In this manner, material can be sent as facsimile images which are never reduced to paper form. The computer also provides improved means for controlling facsimile communications. In other developments, many of the long distance and local telephone companies have begun or have made plans to implement extensive facsimile routing systems and services via the PSTN, controllable by touch tone signals. Rather than a separate cover sheet, a coded command precedes the document, informing the facsimile routing system which recipient or recipients should receive the transmittal image. In other facsimile systems routing and handling information is provided by the use of markable forms similar to the standardized testing forms to carry limited information in machine readable form on the cover sheet.
The Consultative Committee for International Telephone and Telegraph, or CCITT, a standards body for telephony has established recommended standards for facsimile use by member nations. CCITT Group 3 and 4 facsimile systems utilize a compressed digital encoding to minimize the time required for sending the images, and to reduce storage requirements of the compressed images in a store and forward environment.
Other image handling systems exist for the transmission, storage and processing of image data to multiple users using compression techniques and other processing similar to those used in facsimile. For example co-pending U.S. application Ser. No. 07/559,526 to H. M. Morris et al. entitled "Dual Density Digital Image System" and application Ser. No. 07/211,722 to H. M. Morris et al entitled "Object Management And Distribution System" and hereby incorporated by reference discloses the IBM Image Plus System.
All of the prior art systems require a separate document or coded command to route a transmitted image. The cover sheet document or command can get separated from the image during transmission or routing, the result being that the transmitted image is lost within the system. The cover sheet in particular requires substantial additional resource. The touch tone commands of the prior art are not recognized by facsimile devices which are not incorporated in the particular telephone systems in service.
Bar coding has been used for a number of years for the reliable identification of objects marked with a unique code pattern consisting of black and white stripes of varying width or height. Bar codes have not been used heretofore in facsimile. Most Bar Codes are designed with open code sets, and unique code patterns which provide for nearly positive detection of errors. The use of check characters in the coded field further reduces the likelihood of undetected errors to low values.
This invention combines some of the attributes of commonly used Bar Codes with facsimile in a manner such as to permit the embedding of data needed for indexing, or further routing, within the image in machine readable form, which is transparent to the users.